Tire pressure affects vehicle traction (slip) and ride smoothness, tire traction impacts vehicle stability control (e.g., braking), weight distribution affects an area of soil/tire contact, and tire pressure has agronomic impact (e.g., crop yield reduction).
Vehicle traction and stability may be improved in some situations with a greater area of contact between a vehicle and the ground surface. Greater contact may also reduce resultant soil compaction; however, this greater contact may result in decreased fuel efficiency.
Fuel efficiency is increased when rolling friction of a machine is minimized while keeping wheel slip below a certain level. For example, optimal fuel efficiency may be obtained when vehicle tires have relatively high pressure while minimizing wheel slippage. Wet field conditions can cause wheels to slip under high traction load, and thus there is a fuel efficiency benefit to decreasing the tire pressure to reduce wheel slip. However, increased soil compaction, which is detrimental to crops, can occur when the soil is wet and the vehicle tire pressure is high.
Unnecessary compaction of a growth medium such as soil is generally undesirable since it can adversely affect the growing performance of plants. Compaction can occur when growth medium particles are compressed together, which limits the space between such particles for water and air. Soil compaction can also inhibit the growth and development of roots, leading to decreased plant vigor. While some forms of compaction are virtually unavoidable due to causes beyond human control such as heavy rain, it would be desirable to mitigate other types of compaction that are human-caused, such as compaction caused by vehicles used to process materials in a field, forest or worksite such as a construction worksite. U.S. Pat. No. 7,302,837, which is hereby incorporated by reference as background material, attempts to mitigate compaction caused by an implement using soil characteristics and the load of the implement.
What is needed is a mechanism to control the pressure at an interface between a machine and a surface the machine is on in a way which optimizes fuel efficiency while minimizing soil/crop damage.